Jonathan Aitchison

Unlocking the green economy potential of REE in deep marine sediments

Rare Earth Elements (REE) and ‘new economy’ minerals hold a key to Global Environmental Futures. They have a critical role in attaining the key UN sustainable development goals of renewable clean energy by contributing to new technologies essential to sustainability of Planet Earth. According to the US Geological Survey “among other roles these mineral commodities are vital to renewable energy infrastructure like solar panels, wind turbines and batteries”. Their global supply is heavily influenced by geopolitical factors and known resources are at sub-critical levels. On the 24th of February 2021, when signing an Executive Order on securing America’s critical supply chains the new elected US President Joe Biden noted that, “key minerals and materials, like rare earths, that are used to make everything from harder steel to airplanes.”

Traditionally, REE are known to be more common in carbonatites, alkaline igneous systems, ion-absorption clay deposits, monazite-xenotime-bearing placer deposits and hypersaline lake deposits the extent and global distribution of which is limited. Recent discoveries that deep marine sediments on the Pacific Ocean seafloor have high REE abundance suggests other source possibilities. Although REE recovery of such deposits is presently impractical the global plate tectonic conveyor belt that transports oceanic rocks to convergent plate margins at which they are accreted to continental margins offers a possible solution. The same succession of rocks in an Ocean Plate Stratigraphy (OPS) occurs on-land in ancient subduction complexes and offers a potential novel exploration target.

This project aims to study deep marine sediments (chert) of Paleozoic age from ancient subduction complexes in northern NSW and Queensland in eastern Australia,. These locations preserves OPS successions within which we propose to investigate the spatial and temporal distribution of REEs. At macro-scale, the project will determine the REE content within and across geological units, identifying REE “hot spots” and assessing their characteristics. It will also use several in situ techniques to map REE distribution at µm scale and investigate their association with different mineral phases ± microstructures. Results will contribute to fundamental knowledge about accumulation, preservation and transfer of REE in association with marine sedimentary processes. They will also lead towards the establishment of a new type of REE deposit, a key pillar for a sustainable economy future with clean energy.

Diamonds in ophiolite: deep recycling of carbon through the mantle

This project aims to investigate whether the controversial discovery of diamonds in oceanic rocks (known as ophiolites) is a global phenomenon. Even half a century after the introduction of plate tectonic theory, significant knowledge gaps remain regarding the fate of subducting lithosphere and Earth processes deep within the mantle. This project will look at Australian, New Zealand and New Caledonian examples to test the hypothesis that diamonds are ubiquitous in the mantle and occur widely in ophiolites. Results will have major implications for our understanding of how ocean crust grows and rocks in the upper mantle form, as well as providing insight into how organic carbon is drawn from the seafloor deep into the mantle before being recycled back to Earth's surface.

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Paleozoic tectonic evolution of the Terra Australis Orogen

Understanding of the tectonic evolution of eastern Australia and other parts of the Terra Australis Orogen (which stretches via Antarctica to South America) is less well understood than we like to think. Existing models require rigorous testing that can be achieved by using newly acquirable data.

Several projects are available ranging from those that involve from microfossils to detrital zircon geochronology to structural geology and geochemistry. Projects will involve arduous fieldwork in remote locations and require physically fit and resourceful students capable of working in areas not reached by the internet.

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Early Paleozoic radiolarian evolution

Several possible research projects are available working on amzaingly well preserved Paleozoic radiolarians. We are using 3D imaging technology to further understand the evolution of this fossil group. The over-arching project will apply a new transformative technology; X-ray micro computed tomography (3D micro-CT) to the study of Early Paleozoic (530-300 million year old) radiolarian microfossils. This will for the first time allow non-destructive examination to elucidate the internal skeletal architecture of these fossils that is critical to understanding their evolution. Computer reconstruction of 3D images will reveal details upon which an understanding of early phylogenetic relationships within this phylum can be developed. This in turn will allow realization of the full biostratigraphic potential of this important long-ranging group of marine protozoans that commonly occur in great abundance in deep marine sedimentary rocks.

The aim of this project is to unlock the biostratigraphic potential of Early Paleozoic (530-300 m.yr. old) radiolarians using 3D micro-CT technology to elucidate skeletal architecture evolution.